What's going on?

Amazingly, it's nothing more than plain old friction that prevents you from pulling the books apart! Friction is the name we give to the force that opposes the motion of two surfaces in contact. The friction between two single sheets of paper is barely noticeable. But multiply this relatively small amount of friction by a few hundred pages and it adds up to be insurmountable.

The friction between two surfaces depends not only on the materials they are made of but also on how rough or smooth they are. Two smoothly sanded planks of wood will slide past each other more easily than two rough planks of the same type of wood. Adding a fluid such as oil or air between two surfaces can reduce the friction. Fluids used to reduce friction are called lubricants.

The study of friction is called tribology and it's more widespread than you might think. Ball bearings, tyres and automotive lubricants are obvious examples but lipstick, hair conditioners and artificial hips also rely on the study and measurement of friction.

So there you go — a cool science trick, a bit of friction trivia and a new word to add to your smarty-pants vocabulary. That should help you rub a few people the wrong way. Shazam!

(Video item was part of the kids program 'Rollercoaster', which screened from 2005–09.)